Synthesis and structure determination of the adducts of the potent carcinogen 7,12-dimethylbenz(a)anthracene and deoxyribonucleosides formed by electrochemical oxidation: models for metabolic activation by one-electron oxidation

The primary products 7-MBA-12-CH2-C8dG (MBA = methylbenz(a)anthracene), 7-MBA-12-CH2-N7Gua and 12-MBA-7-CH2-N7Gua and the secondary products 7-MBA-12-CH2-C8Gua and 7,12-(CH2OH)2-BA were obtained from the anodic oxidation of 7,12-dimethylbenz(a)anthracene in the presence of dG. The structures were determined by NMR, COSY and NOE spectroscopy. The mechanism of the electrochemical oxidation was proposed to proceed through the reaction of the methyl groups with nucleophilic groups of dA and dG as analyzed from FAB MS/MS and FLNS techniques.